/**
 * 21. 合并两个有序链表
 * https://leetcode.cn/problems/merge-two-sorted-lists/description/
 */

class Solution6 {
    public ListNode mergeTwoLists(ListNode list1, ListNode list2) {
        ListNode ret = new ListNode();
        ListNode cur = ret;
        
        while(list1 != null && list2 != null) {
            if( list1.val <= list2.val) {
                cur.next = list1;
                list1 = list1.next;
            } else {
                cur.next = list2;
                list2 = list2.next;
            }
            cur = cur.next;
        }

        if(list1 != null) cur.next = list1;
        if(list2 != null) cur.next = list2;

        return ret.next;
    }
}
